Improvement in flood-bridges



THOMAS ALFRED BRYAN, 0F BALTIMORE, MARYLAND.

Letters Patent N 106,995, (lated September 6, 1870.

IMPROVEMENT IN FLOOD-BRIDGES.

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The Schedule referred to in these Letters Patent and. making part of the same To all' 'whom Ait may concern:

Be it known that I, THOMAS ALFnED BRYAN, of the city and county of Baltimore, in thc State of' Maryland, have invented certain new and useful Iluprovements in the Construction of Flood-Bridges; and I do hereby declare that the following is a full, clear, andexact description thereof, reference being had to the accompanying drawing making part of this specification, in whichlligure 1, plate 1, is a'side elevation of the improved bridge and its supports.

Figure 2, plate 1, is a top view of the same.

Figure 3, plate 2, is a section taken longitudinally and vertically through the bridge and its supports.

Figure 4, plate 2, is a similar view ofthe same parts shown in fig. 3, indicating the bridge in au elevated position.

Figure 5, plate 2, is a'vertical cross-section through the bridge.

Similar letters of reference indicate corresponding parts in the several figures.

The objects of' this invention are- Filst'hto so construct and support a bridge that it will be sustained, under ordinary occasions, upon a solid foundation, and, when the water in the`stream over which the bridge crosses rises the bridge will be buoyed up, and will then rise and descend with the rise and fall of the water, without seriously interfering with travelacross it.

Second, to extend the side walls, between which the ends of the bridge are received, above the level of the roadway, high enough to prevent overflow of the banks at such points, and to employ movable curtains in combination therewith, which curtains will risc and fall with the ends of thc bridge, and prevent the overflow of' water into the roadway between said side walls.

Third, to provide against the collection of any serious amount of' floating material beneath the ends of' the bridge, and to so construct the passages thereunder that free access can be obtained to them for repairs and other purposes.

Fourth, to adapt the several parts which enter into the constructionofthe bridge to move freely, without liability to bind.

To enable others skilled in the` art to understand my invention, I will explain its construction and operation.

I construct, upon opposite sides of the canal, creek, or stream, on or nearly on a level with the bod of the same, a solid foundation, from which strong walls, A A, of' masonry, ct-ive between them the ends of the bridge B. rllhese walls at 'the sidcvrof the bridge are extended above .the level of the roadway, above the highest watermark, but the walls at the extremities of bridge, in

are erected, which are adapted to re-.

above a given level,

line with the roadway, terminate on a level with the lat-ter, as shown in figs. 3 and 4, and afford supports for the ends of the bridge when the same is not buoyedy up by the rise of the water.

These side and end walls are also` so constructed that the upper portions of them overhang the lower portions, and thereby afford chambers S, which will allow persons to pass around the buoys C, and repair or clear out the chambers, when this is necessary.

rlo the bottom of the bridge B, near each end thereof, hollow floats O are secured. 'lhese tloats or buoys are made of strong boiler-iron, air-tight, and'of a capacity adapted-to float the bridge and allordinary weights which may be upon it. These floats extend transversely across the space between the side walls A A, so that these walls, as welly as the end walls, will serve as guides for thebridge and floats, and resist lateral as well as .longitudinal movements thereof'.

To prevent the ends and outer sides of' the float O from binding between' the side and end walls, in con sequence of the bridge not maintaining an exact level while it is floating iu the water and rising and descending, I curve the extremities of each float, as indicated by the dotted lines, fig. 5. These curves are struck from the upper corners of the ends of each float, so that, whatever inclination the floats may assume, they will not bind between the side walls. The out-er sides of the floats C are curved, so that the tilting of the ends ofthe bridge will not cause it to bind between the opposite end walls. These curves are struck from the upper and outer corners of the opposite. float-s.

Beneath the floats are piles or other suitable supports c rising from the bed of the stream, and intendcd to afford support tothe floats when the ends of the bridge rest upon thc end walls, as shown in figs. 3 and 5.

On thoscsides of the floats C O next thc stream, guards G G are applied, between the side walls A A, and pivoted at p p, so as to swing freely. Each guard extends from a point ucar the level of the roadway to a point near the be'd of thc stream, and thus closes in the space which receives the float, and, while a free circulation of water into and ont of the said space is A not prevented hy the guard, 'it will operate as a protection to the float against thegrea-t force of a rapidly-lowing current. Each guard will also prevent the accumulation ot' large floating substances within the space inclosed by it. By having the guards hinged they can be drawn out from below to allow persons to enter the passages Between the cud walls and the floats, curtains cl d are applied, which are held up in contact with the bottom of the bridge at all times by means of weights w3c, which are hung from cords that are connected to the upper edges of each curtain d, and passed over grooved pulleys e 0, at the upper' ends of columns D.

The curtains d d extend down about as far as the bottoms of' the floats, and, when the bridge isbuoyed up by the rise of water, these curtains will be forced tightly against the upper over-hanging portions of the end walls, by the pressure of' water, thus prevent-ing any considerable amount of vater from escaping into the roadway at these places.

The extremities of each uitain (l are curved, as shown Vby dotted lines, which will prevent the curtain from binding between the side walls A A.

The ends of the floor of the bridge B terminate iu hinged portions B B", the outer ends of which are snstained by rollers or wheels a a, as shown in the drawing.

It will be seen from the above description that I am enabled to maintain a bridge at all times above the level of the water in the stream, and at the same time render the bridge passable and safe. I also proride for keeping back the water from the roadway, notwithstanding the level of the water-'of the stream may be above the level of the roadway. By thus constructing a bridge it will be sustained in just 'as substantial a'manner as` bridges constructed upon the old plans, and, while this is the case, the bridge will rise and descend with the rise and fall of the water after the waterrises above a given level, and will not be in any serious manner affected 'by the force of the eurrent,vinasn1ucb as the floats or buoys C C will be in comparatively still water.

-I am aware that bridges have hitherto been constructed upon ioating objects, so as to rise and fall with the tides, and, therefore, It do not claim, broadly, a oating bridge.

Having described my invention,

Vhat I claim as new, anddesire te secure by Letters Patent, is-

1. The floats C C, arranged beneath the bridge B,

is so constructed with floats that, during an extraortained above the level ot' the water, substantially as described.

THOMAS ALFRED BRYAN.

Witnesses FnANoJs LAMOTTE, JosErH H. LINTON.

within spaces inclosed by side and end walls A A, and

substantially supported upon sclid masonry, and whichdinary rise of water, will be buoyed np, and thus sus-- 

